Bleeding after masturbation? Please help!!

I was in the middle of masturbating with my dildo when I felt a sharp, burning, like I had to urinate sensation which quickly turned painful. I stopped and noticed blood coming from I assume inside my vagina. The pain had me lying on the ground for a moment on the verge of passing out. I'm rather confused as there doesn't seem to be any signs of a tear and the bleeding was only enough to cover one wad of toilet paper and has since then not continued. Should I worry? Has anyone had this happen?